Exhaust gas treatment device and corresponding method for manufacturing same

Abstract

A method for manufacturing an exhaust gas treatment device ( 1 ), which has at least one ceramic substrate body ( 3, 4 ) for exhaust gas treatment in a tubular housing ( 2 ), includes inserting the substrate body ( 3 ) axially into the housing ( 2 ). An axial support ( 13 ), which has a supporting ring ( 14 ) and a ring-shaped support element ( 15 ) held by the supporting ring ( 14 ), is inserted axially into the housing ( 2 ) and is positioned therein such that the axial support ( 13 ) transmits a predetermined axial force ( 28 ) to the substrate body ( 3 ) via the support element ( 15 ). The axial support ( 13 ) is fixed to the housing ( 2 ) with the axially prestressed (predetermined axial force) positioning, in which the supporting ring ( 14 ) is welded to the housing ( 2 ).

What is claimed is: 
     
       1. A method for manufacturing an exhaust gas treatment device, which has at least one ceramic substrate body for exhaust gas treatment in a tubular housing, the method comprising the steps of:
 inserting a substrate body axially into the housing; 
 mounting the inserted substrate body in the housing by means of a mounting mat, wherein the mounting mat envelopes the substrate body in a circumferential direction and is radially prestressed between the substrate body and the housing; 
 providing an axial support, which has a supporting ring and a ring-shaped support element held by the supporting ring; 
 inserting the axial support axially into the housing and positioning the axial support in the housing at an axially prestressed position such that the axial support transmits a predetermined axial force to the first substrate body via the support element in the axially prestressed position; and 
 fixing the axial support to the housing in the axially prestressed position by welding the supporting ring to the housing. 
 
     
     
       2. A method in accordance with  claim 1 , wherein the substrate body is a first substrate body and the mounting mat is a first mounting mat and further comprising the steps of:
 inserting a second substrate body axially into the housing; 
 mounting the inserted housing by means of a second mounting mat, wherein the second mounting mat envelopes the second substrate body in the circumferential direction and is radially prestressed between the second substrate body and the housing, and wherein an axial gap, in which the supporting ring positions the first support element, is formed axially between the first substrate body and the second substrate body. 
 
     
     
       3. A method in accordance with  claim 1 , wherein the supporting ring is pressed radially against the housing to provide a pressed-on state before welding and the supporting ring is welded to the housing in the pressed-on state. 
     
     
       4. A method in accordance with  claim 3 , wherein the supporting ring has an interruption in the circumferential direction. 
     
     
       5. A method in accordance with  claim 1 , wherein:
 the supporting ring has a holding area holding the support element and a fixing area providing a welding region for the welding to the housing; 
 the fixing area is axially inserted, when positioning the axial support in the housing, into an annular gap, which is formed radially between the housing and the substrate body, and is welded in said radial gap to the housing. 
 
     
     
       6. A method in accordance with  claim 5 , wherein an axial edge of the mounting mat, facing the axial support, is arranged axially offset in relation to an axial end face of the substrate body, facing the axial support, so that said axial edge axially limits the radial gap, with which the fixing area axially meshes. 
     
     
       7. A method in accordance with  claim 1 , wherein the welding, for fixing the axial support to the housing, is carried out from an outer side of the housing, radially through the housing. 
     
     
       8. A method in accordance with  claim 7 , wherein the housing is nonperforated in the area of the axial support and is welded to the supporting ring in a nonperforated state. 
     
     
       9. A method in accordance with  claim 1 , wherein the welding is carried out as a laser sweep welding. 
     
     
       10. A method in accordance with  claim 1 , wherein a wire mesh, which is elastically deformed during the axial prestressing of the axial support, is used as the support element. 
     
     
       11. A method in accordance with  claim 1 , wherein
 the supporting ring comprises a U-shaped section comprising an outer leg and an inner leg, for radially positioning the support element, and a base connecting the outer leg with the inner leg for axially positioning the support element; and 
 the outer leg projects axially over the inner leg and is welded to the housing. 
 
     
     
       12. A method in accordance with  claim 2 , wherein:
 an axial dimension of the axial support within the axial gap is smaller than an axial gap width of the axial gap; 
 the gap width is at most 100% and preferably at most 50% greater than the axial dimension of the axial support within the axial gap. 
 
     
     
       13. A method in accordance with  claim 1 , wherein the first substrate body, the axial support and the second substrate body are inserted into the housing through the same axial opening of the housing. 
     
     
       14. An exhaust gas treatment device manufactured according to a method comprising the steps of:
 providing a ceramic substrate body for exhaust gas treatment; 
 providing a tubular housing; 
 inserting the substrate body axially into the housing; 
 mounting the inserted substrate body in the housing by means of a mounting mat, wherein the mounting mat envelopes the substrate body in a circumferential direction and is radially prestressed between the substrate body and the housing; 
 providing an axial support, which has a supporting ring and a ring-shaped support element held by the supporting ring; 
 inserting the axial support axially into the housing and positioning the axial support in the housing at an axially prestressed position such that the axial support transmits a predetermined axial force to the first substrate body via the support element in the axially prestressed position; and 
 fixing the axial support to the housing in the axially prestressed position by welding the supporting ring to the housing. 
 
     
     
       15. An exhaust gas treatment device in accordance with  claim 14 , wherein the substrate body is a first substrate body and the mounting mat is a first mounting mat and further comprising the steps of:
 inserting a second substrate body axially into the housing; 
 mounting the inserted housing by means of a second mounting mat, wherein the second mounting mat envelopes the second substrate body in the circumferential direction and is radially prestressed between the second substrate body and the housing, and wherein an axial gap, in which the supporting ring positions the first support element, is formed axially between the first substrate body and the second substrate body. 
 
     
     
       16. An exhaust gas treatment device in accordance with  claim 14 , wherein the supporting ring is pressed radially against the housing to provide a pressed-on state before welding and the supporting ring is welded to the housing in the pressed-on state. 
     
     
       17. An exhaust gas treatment device in accordance with  claim 16 , wherein the supporting ring has an interruption in the circumferential direction. 
     
     
       18. An exhaust gas treatment device in accordance with  claim 14 , wherein:
 the supporting ring has a holding area holding the support element and a fixing area providing a welding region for the welding to the housing; 
 the fixing area is axially inserted, when positioning the axial support in the housing, into an annular gap, which is formed radially between the housing and the substrate body, and is welded in said radial gap to the housing. 
 
     
     
       19. An exhaust gas treatment device in accordance with  claim 18 , wherein an axial edge of the mounting mat, facing the axial support, is arranged axially offset in relation to an axial end face of the substrate body, facing the axial support, so that said axial edge axially limits the radial gap, with which the fixing area axially engages. 
     
     
       20. An exhaust gas treatment device in accordance with  claim 14 , wherein the welding, for fixing the axial support to the housing, is carried out from an outer side of the housing, radially through the housing.